Electrically controlled ion transfer and pH change near a conducting polymer-coated electrode

Shinohara, Hiroaki; Kojima, Junichiro; Aizawa, Masuo

doi:10.1016/0022-0728(89)85076-4

Cited by 27 publications

(17 citation statements)

References 13 publications

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“…(In CSF, which has a pH of 7.3, the proportions would be expected to be 61% HPO 4 2− and 39% H 2 PO 4 − .) The local pH at the surface of the polymer is unknown, but the local pH is known to be affected by cycling . Nevertheless, the molecule is an anion, rather than a cation.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Conjugated Polymer Actuation under Cerebral Physiological Conditions

Daneshvar

Smela

2014

Adv Healthcare Materials

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Conjugated polymer actuators have potential use in implantable neural interface devices for modulating the position of electrode sites within brain tissue or guiding insertion of neural probes along curved trajectories. The actuation of polypyrrole (PPy) doped with dodecylbenzenesulfonate (DBS) was characterized to ascertain whether it could be employed in the cerebral environment. Microfabricated bilayer beams were electrochemically cycled at either 22 or 37 °C in aqueous NaDBS or in artificial cerebrospinal fluid (aCSF). Nearly all the ions in aCSF were exchanged into the PPy – the cations Na+, K+, Mg2+, Ca2+, as well as the anion PO43−; Cl− was not present. Nevertheless, deflections in aCSF were comparable to those in NaDBS and they were monotonic with oxidation level: strain increased upon reduction, with no reversal of motion despite the mixture of ionic charges and valences being exchanged. Actuation depended on temperature. Upon warming, the cyclic voltammograms showed additional peaks and an increase of 70% in the consumed charge. Bending was, however, much less affected: strain increased somewhat (6-13%) but remained monotonic, and deflections shifted (up to 20%). These results show how the actuation environment must be taken into account, and demonstrate proof of concept for actuated implantable neural interfaces.

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Section: Resultsmentioning

confidence: 99%

Characterization of Conjugated Polymer Actuation under Cerebral Physiological Conditions

Daneshvar

Smela

2014

Adv Healthcare Materials

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“…Shinohara et al also showed electrically controlled ion transfer and pH change near a conducting polymer coated electrode in an aqueous solution containing 0.1 M NaBr [31]. As they described, we may also consider that OH ( ion transfer takes place simultaneously with electrolyte anions into or from the PPY film during the oxidation-reduction process of PPY microtubules at pH /5.…”

Section: Ion Exchange In Ppy Filmsmentioning

confidence: 81%

“…Ion transport in conducting polymers was studied by different analytical techniques such as X-ray photoelectron spectroscopy [19 Á/21], scanning electrochemical microscopy [22], luminescence [23,24], electrochemical quartz crystal microgravimetry [21,25 Á/30], rotating ring-disk voltammetry [31,32]. For PPY the dominant ionic species depends on the choice of the dopant anion and the solvent/electrolyte system [33,34].…”

Section: Introductionmentioning

confidence: 99%

In situ measurement of pH in the interior of conducting polymer microtubules

Nath

Kanungo

Contractor

2003

Journal of Electroanalytical Chemistry

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Visible spectral absorption studies of an indicator trapped in the microenvironment of polypyrrole (PPY) and polyaniline (PANI) films were used to investigate the change in pH accompanying changes in oxidation state of the polymer. An indicator, bromophenol blue was incorporated in the conducting polymer film during the electropolymerization process. In situ UV Á/vis spectra of these films were recorded in aqueous solution of KCl. The results obtained show that with increasing potential of the film, the pH of the microenvironment decreases both for PPY and PANI. The change in pH is greater in the potential range where the change in electronic conductivity is also greater.

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“…For this reason, the Au|PEDOT|0.1 mol dm −3 H 2 SO 4 electrode seems to be a promising target for studying the counter-ion flux accompanying the charging and discharging processes, as well as the degradation of the polymer film. Similar studies have already been carried out by the use of rotating ring-disk electrodes [27][28][29], but these were confined to target systems where electrochemically oxidable (usually halide) counter-ions were involved in the flux, providing means for faradaic detection. Sulphate, the most predominant counter-ion in the system studied here, is not detectable by such means; yet it may be specifically adsorbed on a bare gold ring [30] at well-chosen potentials, causing measurable changes of the interfacial capacitance.…”

Section: Rrde Studies Based On Capacitance Measurements On the Ring Ementioning

confidence: 92%

Apparatus and methods for using a rotating ring–disk electrode with potentiodynamic control of both working electrodes

Vesztergom

Kovács

Ujvári

et al. 2017

Tm - Technisches Messen

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When studying electrochemical processes, one of the most widely used methods of determining the reaction pathway is an electrochemical assay of products using a rotating ring–disk electrode (RRDE). An RRDE tip consists of two electron conducting parts: a centrally located disk and a ring around it. When brought into contact with an electrolyte solution, the disk and the ring both form electrodes, the potentials of which can be independently controlled by a bi-potentiostat. When the tip is rotated, reactants from the solution arrive at the disk where they undergo an electrode reaction (oxidation or reduction) at a given rate, depending on the rotation speed. The formed products leave the disk surface and due to forced convection make their way towards the ring electrode where they can undergo another electrode reaction and can thus be detected. Normally, one applies potentiostatic control to at least one of the electrodes when carrying out an RRDE experiment; albeit the simultaneous potentiodynamic perturbation of the electrodes offers an increased applicability range. This paper presents the construction of a measuring system capable for the “bi-potentiodynamic” perturbation of two working electrodes, and demonstrates the use of such methods in case of a few chosen example systems.

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Electrically controlled ion transfer and pH change near a conducting polymer-coated electrode

Cited by 27 publications

References 13 publications

Characterization of Conjugated Polymer Actuation under Cerebral Physiological Conditions

Characterization of Conjugated Polymer Actuation under Cerebral Physiological Conditions

In situ measurement of pH in the interior of conducting polymer microtubules

Apparatus and methods for using a rotating ring–disk electrode with potentiodynamic control of both working electrodes

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